Unit 1 Objectives - Mr. Roderickmrroderick.com/packets/unit1packet.pdf · Page 1 of 1 Unit 1 Objectives.docx Unit 1 – Atomic Theory Objectives At the end of this unit, you’ll

Page 1 of 1 Unit 1 Objectives.docx

Unit 1 – Atomic Theory Objectives

At the end of this unit, you’ll be able to…

� Understand that the modern model of the atom has evolved over a long period

of time through the work of many scientists

� Discuss the evolution of the atomic model

� Relate experimental evidence to models of the atom

� Identify the subatomic particles of an atom (proton, neutron, and electron)

� Know the properties (mass, location, and charge) of subatomic particles

� Determine the number of protons, neutrons, and electrons in a neutral atom and

an ion

� Differentiate between atomic number, mass number, and (average) atomic mass

� Differentiate between an anion and a cation

� Understand the derivation/basis of the atomic mass unit (amu)

� Distinguish between ground and excited state

� Identify and define isotopes

� Calculate the (average) atomic mass for all isotopes of an element

� Write electron configurations

� Generate Bohr diagrams

� Differentiate between kernel and valence electrons

� Draw Lewis Dot Diagrams for an element or an ion

1-1

Unit 1 Vocab

Term Definition

Allotrope one or more forms of an elementary substance.

AnION negatively charged atom; an atom that gains an electron

Atomthe basic unit of structure for all matter; can’t be broken down any further by

chemical means

Atomic Mass the average mass of all naturally occurring isotopes for an element

Atomic Mass unit (a.m.u.) 1/12th the mass of a Carbon-12 atom; the mass of one proton or one neutron

Atomic number the number of protons in an atom of a given element

CatION positively charged atom; an atom that loses an electron

Compoundtwo or more atoms of DIFFERENT ELEMENTS chemically combined; always the

same ratio

Electronvirtually MASSLESS (teenie, tiny) NEGATIVELY CHARGED particle found

OUTSIDE the nucleus

Electron Configuration the arrangement of electrons in an atom or molecule

Element particles that all have the same number of protons in the nucleus

Excited statewhen an atom absorbs energy and one or more of its electrons “jump” to an orbital

further from the nucleus

Ground statewhen all electrons within an atom fill the lowest energy orbitals; when the electrons

are where they would “normally” be

Ion a charged atom; an atom that gains or loses an electron

Isotopean atom of an element with the same number of protons (atomic #) but a different

number of neutrons

Kernel electron(s) any electrons found inside the valence shell; the innermost electrons

Lewis Dot Diagramrepresentation of an atom or molecule using only the element symbol and the

valence electron arrangement

Mass numberthe mass of a given isotope of an element; the sum of the masses of protons and

neutrons

Neutronsubatomic particle with a MASS of 1 amu (atomic mass unit), and a CHARGE of

zero found WITHIN THE NUCLEUS; (NEUTRAL)

Nuclear Chargeelectric charge within the nucleus of an atom; equal to the # of protons (always

positive!)

Nucleonsany (subatomic) particle found in the nucleus of an atom; a PROTON or a

NEUTRON

Nucleus the DENSE, POSITIVE, CENTRAL core of an atom

Orbitset paths that electrons take around nucleus according to Planetary/Bohr Model

(similar to the paths that planets take around the sun)

Orbitala region where electrons of an atom can be found according to Wave-Mechanical

Model

Planetary Model (A.K.A

Bohr Model)

atomic model constructed by Neils Bohr that proposes all electrons can be found in

orbits or paths outside nucleus (electrons must gain or lose energy to jump from one

orbit to another)

Protonsubatomic particle with a MASS of 1 amu (atomic mass unit), and a CHARGE of +1

found WITHIN THE NUCLEUS

Quantum Theory used to describe the dual nature of matter; electrons behave like particles and energy

Page 1 of 2

1-2

Unit 1 Vocab

Term Definition

Valence electron(s)the outermost electrons in an atom (there can NEVER be more than 8 valence

electrons; known as the OCTET RULE)

Wave-Mechanical Modelstates that electrons don’t travel in fixed orbits, but that we can use mathematic

principals to predict where electrons are most likely to be found

Page 2 of 2

1-3

Name____________________________ Date ________________

Period ________________

Page 1 of 2 1.1 w-1 Early Discoveries.docx

Atomic Theory - Early Discoveries T/F

_____1. Democritus was one of the first people to suggest the idea of an atom.

_____2. Democritus thought that atoms were the smallest possible particles.

_____3. Democritus believed that atoms contained electrons.

_____4. Democritus tested his ideas experimentally.

_____5. Democritus said that atoms could not be compressed or destroyed.

_____6. Democritus believed that atoms of different elements had different densities.

_____7. Democritus thought that all atoms were identical.

_____8. Democritus based his ideas of the English physicist J.J. Thomson.

_____9. Democritus said that different arrangements of atoms gave substances their different properties.

Answer the following.

1. Who put forward the first atomic theory based on experimental observations?

2. What did he (#10) observe to reach his theory?

3. What did this person believe was special about atoms of the same element?

4. The diagram on the right shows an early model of the atom. Who suggested

this model of the atom?

5. What was it called?

6. What were the small particles scattered through the atom believed to be?

7. What experimental evidence led to this model of the atom?

1-4

Name____________________________ Date ________________

Period ________________

Page 2 of 2 1.1 w-1 Early Discoveries.docx

Match each scientist to their discovery/idea and the date that it occurred.

Date Discovery Dates Discoveries

8. Robert Millikan ______ ______ a- 5th

century B.C. w- all atoms contain electrons

9. Joseph John

Thomson

______ ______ b- 1803 x- Everything can be divided

into “matter” or “vacuum”

10. Democritus ______ ______ c- 1897 y- The mass of an electron is

1/1836 of the mass of a

hydrogen atom

11. John Dalton ______ ______ d- 1909 z- Atoms of different elements

are different.

1-5

Name____________________________ Date ________________

Period ________________

Page 1 of 4 1.2 w-1 atomic theories.pub

Atomic Theory - Early Discoveries

1

2

3

4

5

1-6

Name____________________________ Date ________________

Period ________________


6

7

8

9

10

1-7

Name____________________________ Date ________________

Period ________________


11 through 13

12

13

11

12

13

1-8

Name____________________________ Date ________________

Period ________________


14

14

1-9

Name____________________________ Date ________________

Period ________________

Page 1 of 3 1.3 w-1 atoms.pub

Atoms

3

4

5

6

7

8

9

10

11

1-10

Name____________________________ Date ________________

Period ________________


11

12

14

15

16

18

1-11

Name____________________________ Date ________________

Period ________________


19

20

21

22

23

24

Particle Symbol Charge Mass (amu)

Electron e-

Proton p+

Neutron n0

25. Complete the table

26. Nuclear reactions affect the nucleus; what do chemical reactions affect? ________________________

27. If an atom has seven electrons, how many protons does it have? _____________

28. If an atom has electrons added or removed it becomes charged. What is it now called?___________

1-12

Name____________________________ Date ________________

Period ________________

Page 1 of 3 1.4 w-1 Atomic Structure Worksheet.docx

Atomic Structure Worksheet

Fill in the blanks in the following table. Note: The mass may not match the mass on your periodic table. Assume

all atoms are neutral

Atomic

symbol

Atomic

number

Protons Neutrons Electrons Mass

number

C 8

12 24

31 40

40 89

30 35

42 98

W 183

105 71

95 243

Cr 27

83 209

90 142

Md 259

Sc 80

40 51

Note that there are 2 different atoms of Zr (zirconium) listed. Which subatomic particle is different from one to

the other?__________________________________

1-13

Name____________________________ Date ________________

Period ________________


Atomic Theory- Neutral Atoms and their subatomic parts Round the atomic mass that you find on the Periodic Table for that element.

How many protons, neutrons, and electrons are present in the following neutral atoms?

What is the name of the element that has neutral atoms that contain:

5 protons?

_____________________

17 protons?

_____________________

25 protons?

_____________________

82 protons?

_____________________

92 protons?

_____________________

16 electrons?

_____________________

32 electrons?

_____________________

1 electron?

_____________________

8 electrons?

_____________________

2 electrons?

_________________

1-14

Name____________________________ Date ________________

Period ________________


Determine the number of p, n, e for the following ions: Cu

2+ Li

+ O

2-

p =

n =

e =

Cl- Al

3+ I

7+

Atom or Ion # protons # electrons # neutrons Atomic # Mass #

Lithium1+

Phosphorus3-

Vanadium

Krypton

Barium4+

Uranium5-

1-15

Name____________________________ Date ________________

Period ________________

Page 1 of 2 1.5 w-1 isotopes.docx

Isotopes

For the following atoms/ions determine the number of protons, neutrons, electrons, mass number, and

nuclear charge.

Atom or

Ion # protons # electrons # neutrons Mass #

Nuclear

Charge

15N

Cu+2

8B

+3

17O

F-1

206Pb

208Pb

Ag+1

Zn+2

Mg

S-2

Which of the above atoms are isotopes of one another? ________________ Explain how you know this.

_____________________________________________________________________________________

1-16

Name____________________________ Date ________________

Period ________________

Page 2 of 2 1.5 w-1 isotopes.docx

For the following atoms/ions determine the number of protons, neutrons, electrons, mass number, and

nuclear charge.

Atom or

Ion # protons # electrons # neutrons Mass #

Nuclear

Charge

Al+3

37Cl

23Na

+1

He

15O

-2

14C

C

Au+3

U

222Rn

Cu+1

Cu+2

Which of the above atoms are isotopes of one another? ________________ Explain how you know this.

_____________________________________________________________________________________

1-17

Name____________________________ Date ________________

Period ________________

Page 1 of 3 1.5 w-2 Average Atomic Mass.docx

Average Atomic Mass Calculate the atomic mass of each of the following isotopes. SHOW ALL WORK.

Element Mass Percent Abundance

1) copper-63 62.9396 amu 69.17%

copper-65

64.9278 amu 30.83%

2) uranium-235 235.0439 amu 0.72%

uranium-238

238.0510 amu 99.28%

3) hydrogen-1 1.0078 amu 99.985%

hydrogen-2

2.0140 amu 0.015%

4) element Q-8 8.0 amu 10.0%

element Q-9 9.0 amu 20.0%

element Q-10 10.0 amu 70.0%

1-18

Name____________________________ Date ________________

Period ________________


Weighted Averages (SHOW ALL WORK!) You can round the masses given to you.

1. Element X exists in three isotopic forms. The isotopic mixture consists of 10.0% 10

X, 20.0% 11

X, and

70.0% 12

X. What is the average atomic mass of this element?

2. Element Y exists in three isotopic forms. The Isotopic mixture consists of 15.0% 21

X, 65.0% 22

X, and

20.0% 23

X. That is the average atomic mass of this element?

3. A mystery element occurs in nature as two isotopes. Isotope A has a mass of 10.0130 amu and its

abundance is 19.9%; Isotope B has a mass of 11.0093 amu and its abundance is 80.1%. From this data,

calculate the atomic mass of the element and show all work. Lastly, identify the element.

4. A mystery element occurs in nature as two isotopes. Isotope A has a mass of 62.939598 amu and its

abundance is 69.17%; Isotope B has a mass of 64.927793 amu and its abundance is 30.83%. From this

data, calculate the atomic mass of the element and show all work. Lastly, identify the element.

5. A mystery element occurs in nature as three isotopes. Isotope A has a mass of 15.994915 amu and its

abundance is 99.762%; Isotope B has a mass of 16.999132 amu and its abundance is 0.0380%; Isotope C

has a mass of 17.999160 amu and its abundance is 0.2000%. From this data, calculate the atomic mass of

the element and show all work. Lastly, identify the element.

1-19

Name____________________________ Date ________________

Period ________________


6. A sample of cesium is 75% 133

Cs, 20% 132

Cs, and 5% 134

Cs. What is the average atomic mass?

Determine the average atomic mass of the following mixtures of isotopes.

7. 80% 127

I, 17% 126

I, 3% 128

I

8. 50% 197

Au, 50% 198

Au

9. 15% 55

Fe, 85% 56

Fe

10. 99% 1H, 0.8%

2H, 0.2%

3H

11. 95% 14

N, 3% 15

N, 2% 16

N

12. 98% 12

C, 2% 14

C

1-20

Name____________________________ Date ________________

Period ________________

Page 1 of 3 1.6 w-1 electron configurations.docx

Electron Configuration Construct Ground State Bohr Diagrams for the first 20 Elements

For each element, write its name, the number of protons and neutrons, and draw the electrons in their orbitals.

1-21

Name____________________________ Date ________________

Period ________________


1-22

Name____________________________ Date ________________

Period ________________


Write the electron configuration for the first 20 elements.

Element Electron

Configuration

1

2

3

4

5

6

7

8

9

10

Element Electron

Configuration

11

12

13

14

15

16

17

18

19

20

1-23

Name____________________________ Date ________________

Period ________________

Page 1 of 3 1.7 w-1 Lewis Dot.docx

Lewis Dot

Construct Lewis Dot structures for the first 20 Elements

For each element, write its name, the number of protons and neutrons, and draw the Lewis Dot Structure

# Valence e- ____

# unpaired valence e- ____

# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# Valence e- ____


1-24

Name____________________________ Date ________________

Period ________________


# of bonds _____ # of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

1-25

Name____________________________ Date ________________

Period ________________


# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

# Valence e- ____


# of bonds _____

1-26

Name____________________________ Date ________________

Period ________________

Page 1 of 4 1.8 w-1 ground vs excited electrons.docx

Ground State vs. Excited Electrons

Electron

Configuration Identity Ground/Excited

1) 2-8-1

2) 2-8-16-3

3) 2-8-2

4) 2-7-8

5) 1-3

6) 2-8-6

7) -18-32-18-4

8) -18-32-17-3

9) 2-7

10) 1-8

Give an electron configuration for the following (unless it states excited, assume ground state.):

11. Sulfur in its ground state. ______________________

12. Helium in an excited state. ______________________

13. Give the ground state electron configuration for calcium. _____________________

14. Give the correct ground state electron configuration for the Ca+2 ion. ______________________

15. How many valence electrons are there in atom of bromine? ________

16. How many valence electrons are there in a Cl- ion? ________

17. How many kernel electrons are there in a phosphorus atom? ________

18. How many valence electrons are there in a neon atom? ________

19. How many principal energy levels are there in an iron atom? ________

1-27

Name____________________________ Date ________________

Period ________________


20. When atoms of an element are emitting a certain wavelength (or color) of light, it means that

a) the atoms have gained energy and electrons have jumped to an excited state.

b) the atoms have gained energy and electrons have fallen back to the ground state.

c) the atoms have lost energy and electrons have fallen back to the ground state.

d) the atoms have lost energy and electrons have jumped to an excited state.

Use the emissions spectra results below to answer questions 21 and 22:

21. According to these experimental spectra results, the unknown gas is a mixture of which gases? ___________

22. The lines on the visible light spectrum for the gases above represent

a) electrons jumping to the same excited state or energy level.

b) electrons falling back down to their ground state from the same energy level.

c) electrons jumping to multiple excited states or energy levels.

d) electrons falling back down to their ground state from multiple energy levels.

23. How do the energy and the most probable location of an electron in the third shell of an atom compare to the

energy and the most probable location of an electron in the first shell of the same atom?

a) In the third shell, an electron has more energy and is closer to the nucleus.

b) In the third shell, an electron has more energy and is farther from the nucleus.

c) In the third shell, an electron has less energy and is closer to the nucleus.

d) In the third shell, an electron has less energy and is farther from the nucleus.

24. An atom of oxygen is in an excited state. When an electron in this atom moves from the third shell to the

second shell, energy is

a) emitted by the nucleus

b) absorbed by the nucleus

c) emitted by the electron

d) absorbed by the electron

25. Which electron configuration could represent a strontium atom in an excited state?

a) 2–8–18–7–1

b) 2–8–18–8–1

c) 2–8–18–7–3

d) 2–8–18–8–2

1-28

Name____________________________ Date ________________

Period ________________


26. Imagine an emission spectrum produced by a container of hydrogen gas.

Changing the amount of hydrogen in the container will change the colors of the lines in the spectrum.

a) True

b) False

27. In the previous question, changing the gas in the container from hydrogen to helium will change the colors of

the lines occurring in the spectrum.

a) True

b) False

28. An absorption spectrum appears as a continuous spectrum interrupted by a series of dark lines.

a) True

b) False

29. Emission spectra are characterized by narrow bright lines of different colors.

a) True

b) False

1-29

Name____________________________ Date ________________

Period ________________


1-30

Name____________________________ Date ________________

Period ________________

Page 1 of 4 1 Practice Test.docx

Unit 1 Practice Test 1) What is the total number of valence electrons in an atom with the electron configuration 2-8-5? a) 2 b) 5 c) 8 d) 15 2) A Ca2+ ion differs from a Ca0 atom in that the Ca2+ ion has a) more electrons b) more protons c) fewer protons d) fewer electrons 3) Which particles are referred to as nucleons (subatomic particles located in the nucleus)? a) protons and neutrons c) neutrons, only b) protons and electrons d) neutrons and electrons 4) What is the mass number of an atom that contains 19 protons, 19 electrons, and 20 neutrons? a) 39 b) 19 c) 58 d) 20 5) What term refers to the region of an atom where an electron is most likely to be found? a) quantum b) spectrum c) orbital d) orbit 6) The nucleus of an atom consists of 8 protons and 6 neutrons. The total number of electrons present in a neutral atom of this element is a) 6 b) 8 c) 2 d) 14 7) What is the maximum number of electrons that can occupy the third principle energy level? a) 18 b) 8 c) 10 d) 3 8) Atoms of 16O, 17O, and 18O have the same number of a) protons, but a different number of electrons c) protons, but a different number of neutrons b) electrons, but a different number of protons d) neutrons, but a different number of protons 9) All atoms of an element have the same a) number of neutrons c) atomic number b) atomic mass d) mass number 10) The atomic number is always equal to the total number of a) neutrons in the nucleus c) neutrons plus protons in the atom b) protons in the nucleus d) protons plus electrons in the atom 11) How many protons are in the nucleus of an atom of beryllium? a) 2 b) 4 c) 9 d) 5 12) Which subatomic particle is negative? a) proton b) neutron c) electron d) nucleus 13) Which of the following particles has the least mass? a) neutron b) proton c) electron d) hydrogen nucleus 14) A sample of element X contains 90% X-35 atoms, 8.0% X-37 atoms, and 2.0% X-38 atoms. The average atomic mass will be closest to which value? a) 35 b) 36 c) 37 d) 38

1-31

Name____________________________ Date ________________

Period ________________


15) What is the total number of electrons in an Mg+2 ion? a) 10 b) 24 c) 2 d) 12 16) Which of the following electron configurations represents an atom in the excited state? a) 2-8 b) 2-8-1 c) 2-6-1 d) 2-1 17) Which principal energy level of an atom contains an electron with the lowest energy? a) 3 b) 4 c) 1 d) 2 18) The atomic mass of an element is defined as the weighted average mass of that element’s a) naturally occurring isotopes c) radioactive isotopes b) least abundant isotope d) most abundant isotope 19) Compared to the entire atom, the nucleus of the atom is a) smaller and contains most of the atom’s mass c) larger and contains most of the atom’s mass b) smaller and contains little of the atom’s mass d) larger and contains little of the atom’s mass 20) What is the nuclear charge in an atom of boron? a) +11 b) +6 c) +5 d) +12 21) What subatomic particle was discovered in the cathode ray tube experiment? a) proton b) electron c) neutron d) gravitron Short Answer 22) In 1909, a team of British scientists led by Ernest Rutherford, carried out the Gold Foil Experiment to determine the arrangement of particles in the atom. In this experiment, alpha particles were used to bombard gold foil. a) Most of the alpha particles passed through the gold foil undeflected. What conclusion was made about the structure of the atom based on this observation? (1 pt.) b) A few of the alpha particles were deflected back at the source and toward the screen. What did this observation reveal about the structure of the atom? (1 pt.) 23) An element has two isotopes. 90% of the isotopes have a mass number of 20 amu, while 10% have a mass number of 22 amu. Calculate the atomic mass of the element. Show all work with units. (3 pts.)

1-32

Name____________________________ Date ________________

Period ________________


24) Complete the chart below: (9 pts.)

Substance Atom or Ion? # protons # neutrons # electrons Atomic # Mass number

Mg+2

Rb

Cl-

25) What is the electron configuration for a neutral sulfur atom? (1 pt.) 26) What is the electron configuration for S2-? (1 pt.) 27) Based on the two given substances in question 25 and 26, how can you tell the difference between an atom and an ion? (2 pts.) 28) Draw Bohr Diagrams for the following substances (1 pt. each): 29) Draw Lewis Dot Diagrams for the following substances (1 pt. each):

magnesium Na+

carbon S-2

1-33

Name____________________________ Date ________________

Period ________________


30) What is the total number of valence electrons in an atom of Mg-26 in the ground state? (1 pt.) 31) What is the total number of kernel electrons in an atom of Mg-26 in the ground state? (1 pt.) 32) Write a possible electron configuration that could represent magnesium in the excited state. (1 pt.) 2) How many significant figures are there in the following number: 0.03045? (1 pt.)

1-34

Documents

Unit 1 Objectives - Mr. Roderickmrroderick.com/packets/unit1packet.pdf · Page 1 of 1 Unit 1 Objectives.docx Unit 1 – Atomic Theory Objectives At the end of this unit, you’ll